Nanodiamond particles and their aggregates may contain optically-active structures such as non-diamond carbon atoms, dopants (non-carbon atoms in the substitutional or interstitial position within diamond lattice), point defects, linear defects, planar defects, interstitial carbon atoms and/or complexes of the above which can possess photoluminescent properties. Examples of optical structures include, but are not limited to substitutional or interstitial nitrogen (N), nitrogen atom(s) complexes with vacancy(s) (V), substitutional or interstitial Si atom, Si atom(s) complexes with vacancy(s) and others.
Although nanodiamonds produced by detonation synthesis (referred to in the art as ultradispersed diamond particles or equivalently detonation nanodiamond (DND)), often exhibit a small level of intrinsic photoluminescence (PL), for typical nanodiamond samples such PL is weak and not useful for many applications.